numb = {
    'zero': 6,
    'one': 1,
    'two': 2,
    'three': 3,
    'four': 4,
    'five': 5,
    'six': 6,
    'seven': 7,
    'eight': 8,
    'nine': 9
}

simple_numb = [101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199,
               211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331,
               337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457,
               461, 463, 467, 479, 487, 491, 499, 503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599,
               601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 701, 709, 719, 727, 733,
               739, 743, 751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877,
               881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997]
sc1, sc2 = 0, 0
num = input().split()

if num[0] in numb and num[0] != 'zero' and num[1] in numb and num[2] in numb and len(num) == 3:
    end_num = int(str(numb[num[0]]) + str(numb[num[1]]) + str(numb[num[2]]))
    end_num_plus = end_num
    end_num_minus = end_num
    if end_num in simple_numb:
        print(end_num)
    else:
        while end_num_plus not in simple_numb:
            end_num_plus += 1
            sc1 + 1
        while end_num_minus not in simple_numb:
            end_num_minus -= 1
            sc2 += 1
        if sc1 < sc2:
            print(end_num_plus)
        else:
            print(end_num_minus)
else:
    print('Wrong input')
